Ice-making pbocess



ICE-MAKING PROCESS.

Specification of Letters Patent.

Patented Nov. 25, i949.

Application filed July 27,1918. Serial No. 247,041.

To all whom t may concern:

Be it known that I, GARDNER Torre VOOR- Hnns, a citizen of U. S. A., residing at Boston, in the county of Suffolk and State of Mass., have invented'new and useful Improvements in Ice -Making Processes, of which the following is a specification.

i This invention relates to the process most particularly ofmaking ice in cans or molds by subjecting them to cooling-means and has for its object the rendering of the process more expeditious and economical and making the apparatus therefore considerably cheaper per unit of ice produced.

The objects of my invention are to permit the use of colder brine and so require less cans per ton of icel withouthaving the ice check or crack by so doing and to partly or entirely do away with the present standard type of forecooler and to obtain better economy by performing the cooling and freezing at two or more different suction pressures.

l attain these objects by serz'zztz'm having. the cans of water or of water and lice first in one brine bath and then removing thernwith their cooled water or water and ice to another brine bath, the brine baths being preferably colder in the order of the rogression of the cooling of water or freezin of ice and the refrigerant vapor from a brine baths refrigerator being preferably at a lower suction pressure in the order of the progressive cooling of water and freezin of ice.

y invention is of great importance in connection with my previous inventions of multiple eect compressors hereafter called M. E. C. and of multiple effect receivers, hereafter called M. E. R.

In the drawing which is diagrammatic, Figure 1 is a part sectional elevation of an ice making system, wherein, A is a gas compressingmeans, B is a refrigerant condenser, C 1s a forecooler, D D1 D2 is a brine' tank or tanks, 49 is an M. E. R. and 28 to 28k are ice cans.

As my invention will have its widest application to existing can ice making plants by modifying them to include this invention, ll will first describe the ordinary can system and then show how and where l modify it by incorporating my invention therein and therewith.

ln an ordinary can icesystem using any desired refrigerant duid, such for example float 8b which governs regulating valve 8,

the water being cooled in passing through tank -27- and flowing therefrom through outlet 9. Any desired number of cans may be in tanks D, D1 D2, said tanks being shown broken apart by double lines X, Y, Z, the refrigerator or refrigerators, for the biine tank or tanks D D1 D2 may be of any desired type or construction and may be wholly inside or wholly outside or partly inside and partly outside of tanks D D, D2 and are here shown as coils 5, 10; 6, 11 and 56', `57 located in tankor tanksD D, D2. 28a to 28k inclusive are cans showing dierent stages of the ice making cycle. These cans when in the ice making tank or tanks are externally surrounded by brine 13, circulated in any desired way as by propellers 14, 15, 60 actuated from any desired source of power as by motors 16, 17, 59. The vapor from coils 5, 10, and 6, 11 and 4, 7 fiows by pipes 10, 18, 20 and 11, '19, 20 and 7, 21, 20 to a suction inlet 20 of gas compressing means A. (Gas compressing means A may be of any desired type or construction and more particularly of any desired type'of compression or of absorption apparatus and may consist of one or more ordinary compressor cylinders or absorbers operated at the same or at different suction pressures or may vbe a. pair of cylinders or absorbers acting as compound compressors or absorbers with one or more different suction pressures or may be a M. E. C. or multiple effect absorption system or a compressor equipped with my patented M. E. C. device operated at two or more different suction pressures and may be actuated by or through any desired means or source of energy and if an absorption system may have any desired combination of parts.)

The ammonia vapor is compressed in A by power from any desired source and is discharged therefrom through discharge outlet 22 and through pipe 22, Q3 to 'a cooling coil 23, 1 of condenser B wherein the ammonia is re-liqueed by the cooling action of water dripping over it from perforated pipe 24 and flowing from it through pipe 26 from pan 25. Ice tank D D1 may have movable covers 44. Any desired number of cans may be in brine tank D D1. Water from forecooler C is conducted in any desired way as by pipe 9, 29 and hose 29, 30 to the cans and its quantity may lbe regulated in any desired way as for example by valve 29. When the water is frozen in a can it is lifted from the brine in any desired way as by hoist 3l and is moved in any desired way as by trolley 32 on rail 33 to any desired thawing means as ice dump 34 having spray pipe 35. Here the ice is thawed from the can by the action of the water sprayed on the can and after the block of ice has been removed from itthe can is replaced in the brine bath and is-reflled with water either before or after it has been returned to the brine bath.

Now with the most perfect forecooler possible it is not possible to cool the water therein colder than 32 F. and in actual practice the average forecooler of the type here shown usually cools this water to a minimum of from 3G to 40o or more. The brine bath is usually maintained. at about 150.

In actual practice it is found that brinex colder than 10 to l1O cannot be used for distilled water ice without causing the ice to crack or check in the cans. In making raw water ice the cans may be equipped with any desired means to agita-te or circulate the Vwater therein, as for example by pipe 45 connected to pipe 43 supplied with compressed air which flows out of the bottom of the pipe 45 and up through the water 1n the can, thereby circulating said water. It is evident that the heat transfer from a can with water circulating in it, as 28h, will be more rapid than with a can of still Water as 28, and so it i's seen why a warmer temperature of brine is required for raw water ice making than for distilled water ice making. The usual mininunn temperature. of brine for raw water ice making, that will not cause the ice to crack or check is from 12 to 130. This necessarily warmer temperature of brine for raw water ice than for distilled water ice has worked quite ahardship in the changing of plants from distilled water to raw water ice by materially cutting down the ice making capacity of a given number of cans almost directly proportional to 32 minus brine temperature used, although the compressor could make more ice if a colder brine temperature were allowable, because of colder water to forecooler for raw water ice. From my extensive ob seri'ations of numerous can ice making plants I have observed that the average derive the maximum amount of ice possibley from the economically minimum amount of cans and tanks and coils. I often find that an ice tank will use brine so cold that the can of ice must be placed in the air and thus slowly heated or tempered before the cake is thawed loose from the can, for if Athis is not done the transfer of heat from the thawing means to the ice is so rapid that the ice will crack or vcheck while being thawed loose from the can. From'this it seems fair to deduce a general rule that a certain minimuml rate of`heat flow to ice inl a can must be maintained in order that the ice shall not crack or check. A practical example of this might be, considering stresses set up, that one could take a stick of soft molasses candy and gradually bend it double without breaking it whereas a quick effort to so bend a stick would crack it in two. Now inthe ordinary ice making tank. I) D1 it isseen thaty the brine will be circulated by the propellers between the cans so that it flows. first in contact with one can and then in contact with others in its path and it is evident that with coils in the tank and especially with coils outside the tank that a can full of unfrozen water and Dparticularly with comparatively warm unfrozen water will cause too sudden and too' great a rise in the brine temperature as it comes in contact with frozen orpartly frozen cans of water in its path, so as to cause the ice therein to crack or check.

From this it should be evident that if the metal of the can and thewater therein were 32, then the minimum heating effect on other cans would take place so far as cooling alone is concerned. If now in addition to this the can has some ice formed on its inner surface before it is placed in the cold brine it is evident that the very great insulating effect of this ice will enormously retard the heating effect to the brine circulated past sucha can or on other cans in the future path of that brine and so very materially enable one to use colder brine and thus get more ice per can vwithout cracking or checking the same. It is well known that high suction pressures are much more economical than low suction pressures as regards power consumed for the compressing means, particularly of the compression type and more particularly for the M. E. C. type of refrigerating machine. It is further well known that as the ice progresses in thickness its rate of freezing is greatly retarded and from this it is evident that the comparatively small quantity of ice formed resaca@ to finish up the final freezing of a cake, which takes solong to freeze could advantageously be more quickly formed by a colder brine and for a comparatively small capacity of low suction pressure refrigeration. lt is further well known that the ordinary type of forecooler is a very troublesome piece of apparatus as it tends to coatA its coils with ice formed for no good purpose which tends to insulate said coils and render them less effective.- Now if l do part or all of the work of the forecooler in an ice can it is evident that by so doing l may not only get the water to 32 but that l may also cool the can to 320 and may also advantageously form ice on the cans inner surface and so immerse it in a tank of cold brine with very much less heating effect on adjacent cans and that l may furthermore do all of the cooling and even part of the freezing at a higher suction pressure than heretofore with resultant considerable gains in capacity and economy for a given number of cans and for a given compressor displacement.

Now in Fig. 1 it will be obvious that l can accomplish all of these various improvements by a comparatively simple modification of the standard ice cycle so as to accommodate it for and to the principles of this invention. ln most ice plants there are two or more ice making tanks, in which case l mayuse one of the tanks for cooling the water in the cans and for also starting the freezing of the water into ice. lf l have a single tank as provided with two or more coils and it is evident that l". may use some of these coils for preliminary cooling or cooling and freezing and some for final freezing and that l may put a partition preferably insulated, as 36 in tank D D1 so that l would then have two tanks D and D1. 0r l could eX- tend tank D D1 as shown dotted at DZ, there# by making another or third division.

Any desired number of cans and any desired amount of refrigerating coilsurface may be in one division ofP tank D D,L or in tanks D, D1 and D2, preferably the largest number of 'cans being in that tank or that division of a tank which is most progressed in the thickness of the ice in the cans. nd that a given coil surface,-as for example 5, 10, may be made to considerably increase its heat transfer by increasing the rate of circulation of brine through the operation of propeller 14. Now it is evident that coils 5, 10 and 6, l1 may be operated at the same suction pressure as was before described or that by shutting valve 38 and opening valve 44) l may operate tank D at a higher suc- -tion pressure by conducting the vapor from it through pipe 18, 40, 42, 41 to a high pressure suction inlet 41 of compression means A. Compression means A may have as many suction pressure inlets for as many D D1 such a tank is usually diHerent suction pressures as is desired, a

third suction pressure inlet is shown dotted' as 58. lf l used three suction pressures the lowest could be in tank D1 the medium could be in tank D and the highest could be in forecooler C or l might use more than three suction pressures or l could use three suc-k that was at 28d is shown as having been lifted from tank D at 28 and may contain 32 water or 32 water and some ice 12 as is there shown. Now can 28* may be lowered into tank D1 into position 28. Can 285 has been removed from tank D1 and its cake thawed loose and its can is ready to be replaced in space 28d and ready to `be filled with water from hose Q9, 30. l may introduce my lvl. E. R. into the cycle in which case l open valve 48 and valve 47 becomes the expansion valve for the M. E. R. 49, here the liquid ammonia is cooled at a higher suction pressure than that of the refrigerator 6, 11 because of the passage of the liquid ammonia through the expansion valve 47 into M. E. R. 49, the liquid having cooled itself to the high suction pressures saturated temperature and the vapor thus formed in 49 passes through pipe 5i, 52, a2, al to the ing shut, to expansion valve 6 where its pressure is reduced to the lower suction pressure of coil 6, l1. To those skilled in the art it will be evident that l can use M. E. R. 49 'at any one of the several suction pressures that may be employed in the cycle, but preferably at the highest suction pressure used and also that l can use two or more Rs 4:9 preferably having one less M. E. R. than that of the number of suction pressures used and where each M. E. R. preferably has the next Ahighest suction pressure above that of the refri rator that it supplies with cooled l1qu1d. I hen l change A from an ordinary compressor to a IM. E. C. and when l use two suction pressures, a low one for tank D D, and a higher one for forecooler C and either with or without M. E. R'. 49, l then cool the water from say 900 to say 36 in forecooler C, and may also cool the liquid at the M. E. R. from say 95 to say 20". When l do this l get such an enormous [gain in ice making capacity with the same compressor and cans that except for this invention I am unable to utilize all this gain because to do so without this invention I would cool the brine below the cracking or checking point of ice.

Summing up, it is evident that through this invention I may produce as much or more ice without forecooler C and can make as much or more raw water ice as distilled waterice at one suction pressure and that I can by cooling the Water or by cooling the ammonia or both make much more'ice and Ifor considerable gain in economy at two or more different ysuction pressures and. all without cracking or checking the ice at" the cold or colder than usual brine temperatures resulting.

It is evident that the very wide application of this invention may be applied in other than can ice processes and that the various gains in capacity and economy enumerated may be derived in combinations of thel specific instances herein described or v i-n modifications thereof without departing from the broad general principles of this inwater in a can in a first brine bath and then removing the can of cool water and ice to a second brine bath and continuing the freezing thereof.

3. In a can ice making process the method of Scrz'atz'm cooling water in a can in a rst brine bath and then removing the can of cool water to a second and colder'brine bath and freezing it therein. l

4. In a can ice making process the method of sem'at'm cooling and partly freezing water in a can in a first brine bath and then removing the can of cool water and ice to a second and colder brine bath and continuing the freezing therein.

5. In a can ice making process the method of sewlatz'm cooling water in a can in a first brine bath cooled by a vaporizing refriger` ant and then removing the can of cool Water to 'a second and colder brine bath cooled by a lower temperature vaporizing refrigerant and freezing it therein.

6. In a can ice making process the method of scratz'm cooling and partly* freezing water in a can in a first brine bath cooled by a vaporizing refrigerant and then removing the can of cool Water and partly frozen ice to a second and colder brine bath cooled by a lower temperature vaporizing refrigerant and continuing the freezing therein.

GARDNER TUFTS VOORHEES.

WVitnesses:

S. C. ABBOTT, M. V. MARsToN. 

